1. Field of the Invention
This disclosure relates generally to apparatus and methods for tracking of people or assets. More particularly, this disclosure relates to apparatus and methods for tracking of people or assets wherein motion detection is employed.
2. Background
Tracking systems monitor the movement of targets such as personal assets (personal property), vehicles or people. Generally speaking, tracking systems determine position, and changes in position, of the targets. There are many positioning systems, including but not limited to various satellite positioning systems (SPSs), such as the United States Global Positioning System (GPS), the Russian Glonass system, the European Galileo system, any system that uses satellites from a combination of satellite systems, or any satellite system developed in the future. Furthermore, some positioning determination systems utilize pseudolites or a combination of satellites and pseudolites. Pseudolites are ground-based transmitters that broadcast a ranging code, such as a PN code (similar to a GPS or CDMA cellular signal), modulated on a carrier signal which may be synchronized with time provided by an SPS. Pseudolites are useful in situations where SPS signals from an orbiting satellite might be unavailable. Additional terrestrial ranging sources, for example, such as AFLT may be used as alternative positioning systems.
Tracking systems frequently include one or more mobile tracking devices associated with the target(s) being tracked. Mobile tracking devices operate on portable energy sources, such as, for example, batteries. The mobile tracking devices use energy for various tasks, including but not limited to detection of signals, storage and processing of signals and data, communications, and numerical and other computations. One such computation is the determination of position location. The energy used by the mobile tracking device for computing its position location reduces the duration or lifetime of the portable energy source. Position location determinations require relatively large amounts of energy from a portable energy source.